Process and device for formation of mineral wool and mineral wool products

Abstract

A method is provided to produce fine diameter glass fibers with fewer defects through a combination of lower attenuating gas velocities and the use of spinners having more and smaller holes. The method uses a device for internal centrifugation of mineral fibers including a centrifuge equipped with a peripheral band perforated with orifices distributed in a plurality of annular zones arranged on top of each other, assuming that the centrifuge is in centrifugation position. The device includes at least two annular zones whose number of orifices per unit of surface area differs by a value greater than or equal to 5%, 10%, or 20%.

1. A method of making a glass fiber insulation product, comprising:
 (a) providing at least one glass material; 
 (b) melting the glass material; 
 (c) disposing said molten glass material in a spinner having a plurality of spinner orifices; 
 (d) centrifuging the molten glass material through said plurality of spinner orifices to form a multiplicity of glass streams; 
 (e) attenuating said glass streams with a gas current adjacent an exterior of the spinner to form glass fibers having an average diameter of no greater than about 3.5 microns, said gas current being substantially provided by a burner having a burner pressure of about 10-25 inches of water (250-635 mm CE), said burner having a pair of burner lip portions separated by a width of at least 8 mm; and 
 (f) combining the fibers together with a resinous binder to form an insulation product having an ASTM C 686 parting strength of at least about 100 gf/g, and exhibiting a substantial recovery of its nominal thickness following compression; 
 wherein the spinner of (c) and (d) has a peripheral band that is perforated with orifices distributed in a plurality of annular zones arranged on top of each other with the spinner in centrifugation position, and which includes at least two annular zones whose number of orifices per unit of surface area differs by at least a value of 5%, and wherein the annular zone containing a greatest number of orifices per unit of surface area is located below another annular zone, assuming that the spinner is in centrifugation position, wherein each annular zone of the spinner has orifices grouped in at least one row, with a distance between adjacent orifices in each row being substantially constant in each annular zone, and with the distance between adiacent orifices in each annular zone decreasing from one annular zone to another from a top to a bottom of the peripheral band. 
 
   
   
     2. The method of  claim 1 , wherein said attenuating (e) comprises the burner employing an airflow of about 50,000-100,000 ft 3 /hr. 
   
   
     3. The method of  claim 1 , wherein said attenuating (e) comprises the burner employing a gas flow rate of about 3,000-6,000 ft 3 /hr. 
   
   
     4. The method of  claim 1 , wherein a diameter of the orifices are substantially constant in each annular zone and decrease from one annular zone to another, from the top to the bottom of the peripheral band of the spinner. 
   
   
     5. The method of  claim 1 , wherein said rows are spaced from each other at a distance between 1and 2 mm, with a pitch from one row to the next of between 1 and 2 mm. 
   
   
     6. The method of  claim 1 , wherein a diameter of at least a part of the orifices of the spinner is at most 1.5 mm. 
   
   
     7. The method of  claim 1  wherein a distance between centers of closest orifices neighboring a same annular zone of the spinner is substantially constant over an entire annular zone, and wherein this distance varies from one zone to another by at least 3% and is decreasing from the top to the bottom, with in particular a distance between 0.8 and 3 mm. 
   
   
     8. The method of  claim 1 , wherein the spinner presents an average diameter from 200 mm to 800 mm. 
   
   
     9. The method of  claim 1 , wherein gas current of (e) is produced by an annular burner. 
   
   
     10. The method of  claim 9  wherein the annular burner is a tangential burner that includes a mechanism of giving the gas current a tangential component in relation to an external horizontal edge of the spinner. 
   
   
     11. The method of  claim 1 , wherein each annular zone of the spinner has orifices grouped in at least two rows, with a pitch of the rows in each annular zone decreasing from one annular zone to another from the top to the bottom of the peripheral band of the spinner. 
   
   
     12. A method of making a glass fiber insulation product, comprising:
 (a) providing at least one glass material; 
 (b) melting the at least one glass material; 
 (c) disposing said molten glass material in a spinner having a plurality of spinner orifices distributed in a plurality of annular zones that includes at least two annular zones whose number of orifices per unit of surface area differs by at least a value of 5%, wherein each annular zone of the spinner has orifices grouped in at least one row, with a distance between adjacent orifices in each row being substantially constant in each annular zone, and 
 with the distance between adjacent orifices in each annular zone decreasing from one annular zone to another from a top to a bottom of the spinner; 
 (d) centrifuging the molten glass material through said plurality of spinner orifices to form a multiplicity of glass streams; 
 (e) attenuating said glass streams with a gas current adjacent an exterior of the spinner to form glass fibers having an average diameter of no greater than about 3.5 microns; and 
 (f) combining the fibers together with a resinous binder to form an insulation product exhibiting a substantial recovery of its nominal thickness following compression. 
 
   
   
     13. The method of  claim 12 , wherein a diameter of the orifices are substantially constant in each annular zone and decrease from one annular zone to another, from the top to the bottom of a peripheral band of the spinner. 
   
   
     14. The method of  claim 12 , wherein each annular zone of the spinner has orifices grouped in at least two rows, with a pitch of the rows in each annular zone decreasing from one annular zone to another from the top to the bottom of a peripheral band of the spinner. 
   
   
     15. The method of  claim 12 , wherein said rows are spaced from each other at a distance between 1 and 2 mm, with a pitch from one row to the next of between 1 and 2 mm. 
   
   
     16. The method of  claim 12 , wherein a diameter of at least a part of the orifices of the spinner is at most 1.5 mm. 
   
   
     17. The method of  claim 12 , wherein a distance between centers of closest orifices neighboring a same annular zone of the spinner is substantially constant over an entire annular zone, and wherein this distance varies from one zone to another by at least 3% and is decreasing from the top to the bottom, with in particular a distance between 0.8 and 3 mm. 
   
   
     18. The method of  claim 12 , wherein gas current of (e) is produced by an annular burner. 
   
   
     19. The method of  claim 18 , wherein the annular burner is a tangential burner that includes a mechanism of giving the gas current a tangential component in relation to an external horizontal edge of the spinner.